unsigned long pfn = clamp_t(unsigned long, PFN_UP(start),
start_pfn, end_pfn);
unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end),
unsigned long pfn = clamp_t(unsigned long, PFN_UP(start),
start_pfn, end_pfn);
unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end),